Add shlock(1), a program for the safe creation of lock files from shell
[dragonfly.git] / lib / libc / stdio / vsnprintf.c
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1/*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
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35 *
36 * @(#)vsnprintf.c 8.1 (Berkeley) 6/4/93
37 * $FreeBSD: src/lib/libc/stdio/vsnprintf.c,v 1.12.2.1 2002/09/23 06:58:17 maxim Exp $
19c7a913 38 * $DragonFly: src/lib/libc/stdio/vsnprintf.c,v 1.5 2005/05/09 12:43:40 davidxu Exp $
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39 */
40
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41#include <limits.h>
42#include <stdio.h>
41e8adcb 43#include <stdarg.h>
17ea2221 44#include "local.h"
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45
46int
41e8adcb 47vsnprintf(char *str, size_t n, const char *fmt, va_list ap)
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48{
49 size_t on;
50 int ret;
51 char dummy;
52 FILE f;
19c7a913 53 struct __sFILEX ext;
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54
55 on = n;
56 if (n != 0)
57 n--;
58 if (n > INT_MAX)
59 n = INT_MAX;
60 /* Stdio internals do not deal correctly with zero length buffer */
61 if (n == 0) {
62 str = &dummy;
63 n = 1;
64 }
65 f._file = -1;
66 f._flags = __SWR | __SSTR;
67 f._bf._base = f._p = (unsigned char *)str;
68 f._bf._size = f._w = n;
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69 f._extra = &ext;
70 INITEXTRA(&f);
17ea2221 71 ret = __vfprintf(&f, fmt, ap);
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72 if (on > 0)
73 *f._p = '\0';
74 return (ret);
75}